The present invention relates generally to aerial high voltage transmission line equipment and particularly to apparatus for both supporting a transmission line from a superstructure or tower and suppressing any voltage surge differentials occurring between the transmission line and tower.
Aerial transmission lines spanning the countryside are subjected to numerous hazards. For example, they are subject to severe dynamic loading caused by varying weather conditions such as wide variations in temperature, high winds, snow, icing, line breakage, etc. Consequently, an extreme physical burden is imposed on the insulative devices supporting the transmission lines from the tower. In addition, the transmission lines must be protected from lightning strikes. To this end, current practice is to utilize overhead shield wires in conjunction with a tower footing resistance as low as possible. In those situations where shield wire protection is inadequate or where a low tower footing resistance cannot be achieved, the use of line-type surge arresters separate and distinct from the line insulation has been proposed.
It is accordingly an object of the present invention to provide an insulative transmission line supporting device and a transmission line lightning arrester in a single, integrated structure.
An additional object of the present invention is to provide an integrated structure of the above character, wherein the insulative supporting function is that of a so-called strut insulator.
A further object is to provide a combined insulative support and lightning arrester device for aerial high voltage transmission lines which is efficient in construction and reliable in service over a long useful life.
Other objects of the invention will in part be obvious and in part appear hereinafter.